1. Technical Field
Embodiments of the inventive concept relate to a small signal receiver, and more particularly, to a small signal receiver including a self-biased differential amplifier.
2. Discussion of Related Art
Some systems use a transistor-transistor logic (TTL) interface for high-speed communication or compatibility with other systems rather than a complementary metal oxide semiconductor (CMOS) interface. However, since CMOS processes are used in manufacturing semiconductor integrated circuits (ICs), a TTL-to-CMOS interface is widely used. Accordingly, a CMOS IC may use a small signal receiver to convert a TTL voltage level into a CMOS voltage level.
As semiconductor devices operating at a low power supply voltages have become more common, various small signal receivers have been developed. Of those small signal receivers, a self-biased differential amplifier may be used in mobile devices for which low voltage and low power consumption is important. A self-biased differential amplifier receives a reference voltage and an input voltage, compares them with each other, and outputs a comparison result. The self-biased differential amplifier has a complementary form, can use active-biasing, is less sensitive to processes, temperature and power supply voltages due to a self-bias characteristic given by negative feedback, and can provide a switch current relatively greater than a quiescent bias current.
However, as semiconductor devices get smaller and require lower power, self-biased differential amplifiers may not provide output signals reliably at a low input voltage.